This invention relates to friction materials, and more particularly to friction materials of the kind used for brake pads, brake linings, clutch facings and similar uses.
Friction materials of this kind are generally composed of a thermoset binder, an inorganic fibrous reinforcement and various fillers and other additives. These compositions are required to withstand severe operating temperatures and pressures under repeated application without failure or deterioration in friction properties and the fibrous reinforcement generally used is asbestos. Numerous proposals have been made of compositions containing other inorganic fibrous reinforcement but such materials have so far had limited commercial acceptance.